We propose to complete the refinement and field-testing of our instrument, the Observable Indicators of Nursing Home Care Quality, so that it can be used by other researchers and potentially by consumers and regulators, to assess quality of care on a brief inspection of a nursing home. Building upon our preliminary work of qualitative studies to identify the dimensions of quality of care in nursing homes, we constructed an initial instrument from the descriptive statements from study participants that were observable to measure each dimension. The instrument has been revised four times and field-tested each time in a total of 123 nursing homes in the state; preliminary validity and reliability test results are promising. Three phases of research are planned to complete the development of the instrument for use by other researchers and to assess its utility and psychometric properties as a tool to help consumers and regulators assess nursing home quality of care. During Phase One, the instrument will be field tested in 250 nursing homes in Missouri by experienced health care professionals to establish reliability and Generalizability theory estimates. Field tests with consumer representatives and regulators will be conducted in 30 of the 250 nursing homes. Concurrent validity and known groups analysis validity will be measured using the Minimum Data Set (MDS) quality indicators (Qls). During Phase Two, the instrument will be field tested in 150 nursing homes in two other Midwestern states. A two-stage factor analysis using data from the 400 nursing homes will be used to evaluate the underlying structure of the instrument. During Phase Three, scoring guidelines will be empirically developed using Phase One and Two data. A final field test is planned for the Observable Indicators instrument with consumers who are making the decision to move into a nursing home. In light of current demographic and societal trends, the development of a new measure of quality of care in nursing homes that can be easily administered in under 30 minutes and accurately and reliably measure the complex dimensions of quality is extremely relevant.